Leakage detection device for gas construction

The leakage detection device comprises a machine body, the side wall of the machine body is electrically connected with a display screen, the inner top of the machine body is fixedly connected with an air suction barrel, a movable rod is arranged on the air suction barrel in a sliding and penetrating mode, and the lower end of the movable rod is fixedly connected with a piston. And the upper end of the movable rod penetrates through the machine body. By means of the movable rod, the piston and the pull plate, negative pressure can be formed in the exhaust cylinder by pulling the pull plate upwards, gas in a construction site is collected through the gas inlet pipe, meanwhile, the connecting rod connected to the lower end of the pull plate drives the rack to move, and the meshed gears drive the scraper to rotate through the transmission rod. The filter screen at the end opening of the air inlet pipe can be cleaned, accumulated dust can be scraped off, blockage caused in the air collection process is avoided, m